1. Field of the Invention
The present invention relates generally to an electrical coaxial connector, and more particularly to an improvement in an electrical coaxial connector which has a signal contact member and a grounding contact member insulated from each other to be connected respectively with a core conductor and an outer conductor insulated from each other of a coaxial cable provided with an internal insulator put between the core conductor and the outer conductor for surrounding the core conductor and an external insulator for surrounding the outer conductor, and is used to be coupled with a mating coaxial connector fixed, for example, to a circuit board.
2. Description of the Prior Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
There has been often utilized a coaxial cable having a core conductor, an outer conductor, an internal insulator put between the core conductor and the outer conductor for surrounding the core conductor and an external insulator for surrounding the outer conductor for transmitting high-frequency signals between electrical parts, electric equipments or electronic apparatus. The high-frequency signal transmitted through the coaxial cable is put in a condition of electro-magnetic shield so as to be inactive to leak out from the core conductor or to prevent noises from mixing thereinto from the outside. For example, the coaxial cable is connected with a circuit board on which high frequency signals are dealt with and the high frequency signal is transmitted through the coaxial cable from the circuit board to the outside or from the outside to the circuit board under the condition of electro-magnetic shield.
For connecting the coaxial cable with the circuit board, an electrical coaxial connector is connected with an end of the coaxial cable to be coupled with a mating coaxial connector fixed to the circuit board. The electrical coaxial connector connected with the end of the coaxial cable (hereinafter, referred to as a coaxial cable connector) has a signal contact member with which the core conductor of the coaxial cable is connected and a grounding contact member with which the outer conductor of the coaxial cable is connected. The mating coaxial connector has a central contact member to which the high-frequency signal dealt with on the circuit board is supplied and an outer contact member provided for surrounding the central contact member to be supplied with a ground potential. When the coaxial cable connector is coupled with the mating coaxial connector on the circuit board, the grounding contact member of the coaxial cable connector engages with the outer contact member of the mating coaxial connector to be electrically connected with the same and the signal contact member of the coaxial cable connector comes into press-contact with the central contact member of the mating coaxial connector to be electrically connected with the same.
For such a coupling of the coaxial cable connector with the mating coaxial connector as mentioned above, the mating coaxial connector is fixed to the circuit board with the central contact member and the outer contact member surrounding the central contact member each facing upward on a parts-mountable surface of the circuit board on which various electrical or electronic parts are mounted, so that the coaxial cable connector is moved downward toward the parts-mountable surface of the circuit board to be coupled with the mating coaxial connector in such a manner that the grounding contact member of the coaxial cable connector is engaged with the outer contact member of the mating coaxial connector and the signal contact member of the coaxial cable connector is put in press-contact with the central contact member of the mating coaxial connector. Accordingly, the coaxial cable connector coupled with the mating coaxial connector which is fixed to the circuit board is postured to project from the parts-mountable surface of the circuit board with a predetermined measure of thickness in a direction perpendicular to the parts-mountable surface of the circuit board.
There has been previously proposed one of various types of electrical coaxial connectors, with which a signal contact member is not required for connection with a core conductor of a coaxial cable to be soldered with the core conductor of the coaxial cable so that the electrical coaxial connector is able to be connected easily and appropriately with the end of the coaxial cable, as disclosed in, for example, the Japanese patent application published before examination under publication number 2002-324636 (hereinafter, referred to as published patent document 1).
The previously proposed electrical coaxial connector disclosed in the published patent document 1 comprises a shell (a grounding contact) having an annular engaging portion and a shell-bending portion extending from the annular engaging portion, a connecting terminal member (a signal contact member) having a stationary contact portion and a movable contact portion and a pair of engaging portions each extending from the stationary contact portion, and an insulating member (a housing made of insulator) having a bending portion to be put between the connecting terminal member and the shell. The connecting terminal member is supported by the insulating member and the insulating member is supported by the shell. The stationary contact portion and the movable contact portion extending from the stationary contact portion of the connecting terminal member are so positioned in regard to the annular engaging portion of the shell that the engaging portions extending from the stationary contact portion are surrounded by the annular engaging portion of the shell.
When the electrical coaxial connector proposed previously as mentioned above is connected with the end portion of the coaxial cable to constituting a coaxial cable connector, the core conductor of the coaxial cable is positioned to be correspond to the stationary contact portion of the connecting terminal member, and the movable contact portion of the connecting terminal member, the bending portion of the insulating member and the shell-bending portion of the shell are piled up on the core conductor of the coaxial cable, so that the core conductor of the coaxial cable is put between the stationary contact portion of the connecting terminal member and the movable contact portion of the connecting terminal member to be fixed to and connected with the connecting terminal member and the shell-bending portion of the shell is connected with the outer conductor of the coaxial cable. Then, the coaxial cable connector, that is, the previously proposed electrical coaxial connector disclosed in the published patent document 1 and connected with the end of the coaxial cable, is coupled with a mating coaxial connector fixed to a circuit board, which has a central contact member and an outer contact member surrounding the central contact. In the coaxial cable connector coupled with the mating coaxial connector, the annular engaging portion of the shell is put in engagement with the outer contact member of the mating coaxial connector and the engaging portions extending from the stationary contact portion of the connecting terminal member is put in press-contact with the central contact member of the mating coaxial connector.
When the previously proposed electrical coaxial connector disclosed in the published patent document 1 is connected with the end of the coaxial cable so as to constitute the coaxial cable connector and coupled with the mating coaxial connector fixed to the circuit board, the core conductor of the coaxial cable connected with the connecting terminal member which has the engaging portions extending from the stationary contact portion and positioned to be surrounded by the annular engaging portion of the shell, is put between the stationary contact portion of the connecting terminal member and the movable contact portion of the connecting terminal member. On that occasion, the stationary and movable contacts of the connecting terminal member and the core conductor of the coaxial cable put between the stationary and movable contacts of the connecting terminal member so as to be fixed to and connected with the connecting terminal member are positioned to be piled up on the central contact member of the mating coaxial connector at the inside of the annular engaging portion of the shell. Thereby, the electrical coaxial connector previously proposed for constituting the coaxial cable connector, as disclosed in the published patent document 1, is to be designed to have a measure of thickness thereof on the circuit board to which the mating coaxial connector is fixed, which is increased in a direction perpendicular to the circuit board.
Accordingly, there has been also proposed another electrical coaxial connector in which a measure of thickness thereof on a circuit board to which a mating coaxial connector is fixed is reduced in a direction perpendicular to the circuit board by means of making an improvement in a position where a core conductor of a coaxial cable is connected with a signal contact member of the electrical coaxial connector, as disclosed in, for example, the Japanese patent application published before examination under publication number 2006-179409 (hereinafter, referred to as published patent document 2).
The previously proposed electrical coaxial connector disclosed in the published patent document 2 comprises a metallic shell (a grounding contact member) which has an annular engaging portion, a tongue portion extending from the annular engaging portion and a plurality of pairs of caulking portions formed on the tongue portion, a signal contact member (a contact member) which has a pair of plug connecting terminal portions positioned at the inside of the annular engaging portion of the metallic shell and a pair of cable connecting terminal portions positioned at the outside of the annular engaging portion of the metallic shell, and a housing made of insulator (a insulating housing member) which has a pair of bending portions between which the cable connecting terminal portions of the signal contact are put and is positioned between the signal contact member and the metallic shell. The signal contact member is supported by the housing and the housing is supported by the metallic shell. The cable connecting terminal portions of the signal contact member are positioned to be opposite to each other and the bending portions of the housing are positioned also to be opposite to each other in the same direction as the cable connecting terminal portions of the signal contact member. Each pair of caulking portions formed on the tongue portion of the metallic shell are positioned to be opposite to each other with the bending portions of the housing between.
When the electrical coaxial connector proposed previously as disclosed in the published patent document 2 is connected with an end portion of a coaxial cable to constituting a coaxial cable connector, a core conductor of the coaxial cable is put between the cable connecting terminal portions of the signal contact member positioned at the outside of the annular engaging portion of the metallic shell. Then, each of the caulking portions formed on the tongue portion of the metallic shell to constitute one of the pairs of the caulking portions is bent inside so that the bending portions of the housing are pushed respectively by the caulking portions formed on the tongue portion of the metallic shell to be shifted in its position. Thereby, the cable connecting terminal portions of the signal contact member is moved to approach each other and the core conductor of the coaxial cable is held tightly by the cable connecting terminal portions of the signal contact member to be connected with the signal contact member. Further, each of the caulking portions formed on the tongue portion of the metallic shell to constitute another one of the pairs of the caulking portions is bent inside so that the tongue portion of the metallic shell is connected with an outer conductor of the coaxial cable.
Then, the coaxial cable connector, that is, the electrical coaxial connector proposed previously as disclosed in the published patent document 2 and connected with the end of the coaxial cable, is coupled with a mating coaxial connector fixed to a circuit board, which has a central contact member and an outer contact member surrounding the central contact member. In the coaxial cable connector coupled with the mating coaxial connector, the annular engaging portion of the shell is put in engagement with the outer contact member of the mating coaxial connector and the plug connecting terminal portions positioned at the inside of the annular engaging portion of the metallic shell are put in press-contact with the central contact member of the mating coaxial connector.
The cable connecting terminal portions of the signal contact member are operative to approach each other in a direction perpendicular to a direction along which the annular engaging portion of the metallic shell is moved to engage with the outer contact member of the mating coaxial connector and the bending portions of the housing are operative also to approach each other in the direction perpendicular to the direction along which the annular engaging portion of the metallic shell is moved to engage with the outer contact member of the mating coaxial connector.
In the coaxial cable connector thus constituted with the previously proposed electrical coaxial connector as disclosed in the published patent document 2 and coupled with the mating coaxial connector fixed to the circuit board, the core conductor of the coaxial cable connected with the signal contact member is put tightly between the cable connecting terminal portions of the signal contact member positioned at the outside of the annular engaging portion of the metallic shell so as to be connected with the signal contact member, so that the cable connecting terminal portions of the signal contact member and the central conductor of the coaxial cable held tightly by the cable connecting terminal portions of the signal contact member are not positioned to be piled up on the central contact member of the mating coaxial connector at the inside of the annular engaging portion of the metallic shell. As a result, the electrical coaxial connector previously proposed for constituting the coaxial cable connector, as disclosed in the published patent document 2, is able to be designed to have a measure of thickness thereof on the circuit board to which the mating coaxial connector is fixed, which is reduced in a direction perpendicular to the circuit board.
In the electrical coaxial connector proposed previously as disclosed in the published patent document 2, it is advantageous that the signal contact member is not required for connection with the core conductor of the coaxial cable to be soldered with the core conductor of the coaxial cable and the measure of thickness of the electrical coaxial connector on the circuit board to which the mating coaxial connector is fixed can be reduced in the direction perpendicular to the circuit board, On the other hand, the previously proposed electrical coaxial connector is accompanied with a disadvantage that the housing made of insulator becomes complicated in structure.
That is, the housing of the previously proposed electrical coaxial connector is required to have the bending portions operative to be opposite to each other with the cable connecting terminal portions of the signal contact member between. In addition, the bending portions of the housing are required to be opposite to each other in the direction perpendicular to the direction along which the annular engaging portion of the metallic shell is moved to engage with the outer contact member of the mating coaxial connector fixed on the circuit board and required further to be pushed by the caulking portions formed on the tongue portion of the metallic shell for moving the cable connecting terminal portions of the signal contact member to approach each other when each of the caulking portions formed on the tongue portion of the metallic shell is bent inside. Accordingly, the housing is complicated in its structure so as to require much time for production and assembly thereof and a production cost of the electrical coaxial connector is increased due to the housing.